Assembly Biosciences Reports Third Quarter 2025 Financial Results and Recent Updates

Rhea-AI Summary

Assembly Biosciences (Nasdaq: ASMB) reported Q3 2025 results and program updates on Nov 10, 2025. Key clinical highlights include positive Phase 1b interim results for ABI-5366 showing significant reductions in HSV-2 shedding and genital lesions, and Phase 1a data for ABI-6250 supporting once-daily dosing and progression to Phase 2. Enrollment completed for ABI-5366 and two ABI-1179 cohorts; an HSV data readout is now expected by year-end and a Phase 2 start for ABI-5366 is anticipated mid-2026.

Financials: the company raised $175M in equity, held $232.6M cash at Sept 30, 2025 (runway into late 2027), reported Q3 revenue from Gilead collaboration of $10.8M, R&D $16.6M, and net loss of $9.2M.

Positive

• $175M gross proceeds from equity financing
• Cash balance of $232.6M as of Sept 30, 2025
• ABI-5366 Phase 1b showed significant reductions in HSV-2 shedding
• ABI-6250 Phase 1a PK supported once-daily dosing and Phase 2

Negative

• R&D expense increased to $16.6M in Q3 2025
• General and administrative expense rose to $5.1M in Q3 2025
• Net loss of $9.2M for Q3 2025

Insights

Clinical and Corporate Finance Analyst

Positive clinical readouts and a sizeable equity raise materially strengthen development progress and near-term funding.

Assembly Biosciences reported interim Phase 1b antiviral activity for ABI-5366 with significant reductions in HSV-2 shedding and genital lesion rates and Phase 1a data for ABI-6250 showing a once-daily pharmacokinetic profile and dose-dependent target engagement biomarker increases; these clinical signals support progression to Phase 2 and de-risk the programs at early stages.

The company also raised $175 million and reported cash, cash equivalents and marketable securities of $232.6 million as of September 30, 2025, projecting runway into late 2027. That financing plus collaboration revenue of $10.8 million this quarter materially improves near-term funding for planned development, including an anticipated Phase 2 start for ABI-5366 in mid-2026.

Key dependencies and risks include completion and peer review of the remaining HSV virology analyses and the combined readout expected by end of year, which will determine the strength of clinical signals; subsequent Phase 2 design and enrollment pace will also matter. Watch the end-of-year HSV dataset, initiation of the mid-2026 Phase 2 for ABI-5366, and any updates on collaboration payments or warrant exercises that could extend runway beyond 2028.

– Released positive Phase 1b interim results for long-acting helicase-primase inhibitor candidate ABI-5366 showing significant reductions in viral shedding rate and genital lesion rate in recurrent genital herpes –

– Announced Phase 1a interim results for orally bioavailable HDV entry inhibitor candidate ABI-6250 supporting progression into Phase 2 evaluation –

– Additional interim Phase 1b data readouts from HSV program anticipated to include monthly oral dosing for ABI-5366 and two cohorts of weekly oral dosing for ABI-1179, with data now expected by end of year –

– Raised $175 million gross proceeds from equity financings –

SOUTH SAN FRANCISCO, Calif., Nov. 10, 2025 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today reported financial results and recent updates for the third quarter ended September 30, 2025.

“Our third quarter was marked by significant progress across our pipeline and important data releases, particularly the impressive interim antiviral activity and clinical outcomes data from our Phase 1b study for ABI-5366 in participants with recurrent genital herpes,” said Jason Okazaki, chief executive officer and president of Assembly Bio. “The $175 million equity investment we completed in August enables us to advance both our HSV and HDV programs into Phase 2 while continuing our efforts to discover and develop new programs. With enrollment in our Phase 1b study for ABI-5366 and two cohorts in our Phase 1b study for ABI-1179 now complete, we look forward to sharing additional data updates from our HSV program later this year.”

Third Quarter 2025 and Recent Highlights

• Herpes Simplex Virus (HSV)
  • Released positive interim results from a Phase 1b study of ABI-5366, a long-acting helicase-primase inhibitor development candidate, demonstrating significant reductions in HSV type 2 (HSV-2) shedding rate, high viral load shedding and genital lesion rates in participants with recurrent genital herpes
  • Completed enrollment in the ongoing Phase 1b study of ABI-5366 in participants with recurrent genital herpes
  • Completed enrollment in two cohorts of the ongoing Phase 1b study in participants with recurrent genital herpes for ABI-1179, a second long-acting helicase-primase inhibitor development candidate
  • Presented interim Phase 1b data for ABI-5366 in a late-breaking oral presentation at the 38th Congress of the International Union Against Sexually Transmitted Infections (IUSTI)-Europe
    
• Hepatitis D Virus (HDV)
  
  • Released interim results from a Phase 1a study of ABI-6250, an oral HDV entry inhibitor candidate, showing a pharmacokinetic profile supporting once-daily dosing, and dose-dependent increases in a biomarker of target engagement supporting progression to Phase 2 clinical evaluation in HDV
  • Completed enrollment and follow-up period in the Phase 1a study of ABI-6250 in healthy participants
  • Presented preclinical profiling of ABI-6250 in an oral presentation at the 2025 International HBV meeting

• Hepatitis B Virus (HBV)
  • Presented positive data from a Phase 1b study for ABI-4334, a next-generation, highly potent HBV capsid assembly modulator candidate, in a late-breaking poster presentation at the American Association for the Study of Liver Diseases (AASLD), The Liver Meeting^®

• Financing
  • Raised $175 million in gross proceeds from equity financing with key institutional investors, strengthening financial position to support ongoing and future clinical development

Anticipated Milestones and Events

• Mr. Okazaki and Anuj Gaggar, MD, PhD, chief medical officer, will present in a fireside chat during the Guggenheim 2nd Annual Healthcare Innovation Conference on November 12, 2025
• Interim Phase 1b data readout for the HSV program in participants with recurrent genital herpes now anticipated by end of year from two cohorts of weekly dosing of ABI-1179 and one cohort of monthly dosing of ABI-5366. These datasets are expected to be announced together once all virology analyses are completed
• Initiation of a Phase 2 clinical study of ABI-5366 anticipated in mid-2026
  

ABI-1179 was contributed by Gilead Sciences, Inc. (Gilead) under the collaboration between Assembly Bio and Gilead. ABI-5366, ABI-1179, ABI-6250 and ABI-4334 are investigational product candidates that have not been approved anywhere globally, and their safety and efficacy have not been established.

Third Quarter 2025 Financial Results

• Cash, cash equivalents and marketable securities were $232.6 million as of September 30, 2025, compared to $75.0 million as of June 30, 2025. Assembly Bio’s cash position is projected to fund operations into late 2027. This cash runway guidance does not include potential future payments to Assembly Bio under the collaboration with Gilead or from potential warrant exercises, which would further extend cash runway beyond 2028.
• Revenue from collaborative research with Gilead was $10.8 million for the three months ended September 30, 2025, compared to $6.8 million in the same period in 2024. The change reflects the increase in research and development incurred under the collaboration as well as an increase in collaboration funding.
• Research and development expenses were $16.6 million for the three months ended September 30, 2025, compared to $13.5 million for the same period in 2024. The increase is largely driven by an increase in spending on the Company’s HSV program, as both ABI-1179 and ABI-5366 saw significant enrollment in their respective Phase 1b clinical studies during the current quarter.
• General and administrative expenses were $5.1 million for the three months ended September 30, 2025, compared to $4.3 million for the same period in 2024. The increase was primarily due to higher professional fees and increased stock-based compensation related to performance-based awards.
• Net loss attributable to common stockholders was $9.2 million, or $0.72 per basic and diluted share, for the three months ended September 30, 2025, compared to $9.6 million, or $1.51 per basic and diluted share, for the same period in 2024.
  

About Assembly Biosciences
Assembly Biosciences is a biotechnology company dedicated to the development of innovative small-molecule therapeutics designed to change the path of serious viral diseases and improve the lives of patients worldwide. Led by an accomplished team of leaders in virologic drug development, Assembly Bio is committed to improving outcomes for patients struggling with the serious, chronic impacts of herpesvirus, hepatitis B virus (HBV) and hepatitis delta virus (HDV) infections. For more information, visit assemblybio.com.

Forward-Looking Statements
The information in this press release contains forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to materially differ. These risks and uncertainties include: Assembly Bio’s ability to realize the potential benefits of its collaboration with Gilead, including all financial aspects of the collaboration and equity investments; Assembly Bio’s ability to initiate and complete clinical studies involving its therapeutic product candidates, including studies contemplated by Assembly Bio’s collaboration with Gilead, in the currently anticipated timeframes or at all; safety and efficacy data from clinical or nonclinical studies may not warrant further development of Assembly Bio’s product candidates; clinical and nonclinical data may not differentiate Assembly Bio’s product candidates from other companies’ candidates; Assembly Bio’s ability to maintain financial resources and secure additional funding necessary to continue its research activities, clinical studies, and other business operations; the U.S. federal government shutdown and potential effects of changes in government regulation, including as a result of the change in U.S. administration in 2025; results of nonclinical studies may not be representative of disease behavior in a clinical setting and may not be predictive of the outcomes of clinical studies; and other risks identified from time to time in Assembly Bio’s reports filed with the U.S. Securities and Exchange Commission (the SEC). You are urged to consider statements that include the words may, will, would, could, should, might, believes, hopes, estimates, projects, potential, expects, plans, anticipates, intends, continues, forecast, designed, goal or the negative of those words or other comparable words to be uncertain and forward-looking. Assembly Bio intends such forward-looking statements to be covered by the safe harbor provisions contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. More information about Assembly Bio’s risks and uncertainties are more fully detailed under the heading “Risk Factors” in Assembly Bio’s filings with the SEC, including its most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. Except as required by law, Assembly Bio assumes no obligation to update publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

Contacts:

Investors:
Patrick Till
Meru Advisors
(484) 788-8560
investor_relations@assemblybio.com 

Media:
Sam Brown LLC
Alyssa Kuciunas
(331) 481-3751
ASMBMedia@sambrown.com

	ASSEMBLY BIOSCIENCES, INC.
	CONDENSED CONSOLIDATED BALANCE SHEETS
	(In thousands except for share amounts and par value)
			September 30,				December 31,
				2025				2024
			(Unaudited)
	ASSETS
	Current assets
	Cash and cash equivalents		$	22,534			$	38,344
	Marketable securities			210,023				73,735
	Accounts receivable from collaboration with a related party			912
	Prepaid expenses and other current assets			3,343				3,424
	Total current assets			236,812				115,503
	Property and equipment, net			229				284
	Operating lease right-of-use assets			2,644				3,069
	Other assets			312				312
	Total assets		$	239,997			$	119,168
	LIABILITIES AND STOCKHOLDERS' EQUITY
	Current liabilities
	Accounts payable		$	1,683			$	585
	Accrued research and development expenses			3,058				2,273
	Other accrued expenses			5,728				6,862
	Deferred revenue from a related party - short-term			42,363				37,622
	Operating lease liabilities - short-term			548				461
	Total current liabilities			53,380				47,803
	Deferred revenue from a related party - long-term			1,715				35,378
	Operating lease liabilities - long-term			2,207				2,628
	Total liabilities			57,302				85,809
	Commitments and contingencies
	Stockholders' equity
	Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued or outstanding			—				—
	Common stock, $0.001 par value; 150,000,000 shares authorized as of September 30, 2025 and December 31, 2024; 15,816,987 and 7,457,240 shares issued and outstanding as of September 30, 2025 and December 31, 2024, respectively			16				7
	Additional paid-in capital			1,036,906				859,488
	Accumulated other comprehensive loss			(90	)			(211	)
	Accumulated deficit			(854,137	)			(825,925	)
	Total stockholders' equity			182,695				33,359
	Total liabilities and stockholders' equity		$	239,997			$	119,168

	ASSEMBLY BIOSCIENCES, INC.
	CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
	(In thousands except for share and per share amounts)
	(Unaudited)
			Three Months Ended September 30,								Nine Months Ended September 30,
				2025				2024				2025				2024
	Collaboration revenue from a related party		$	10,789			$	6,845			$	29,834			$	21,163
	Operating expenses
	Research and development			16,587				13,515				47,563				41,653
	General and administrative			5,085				4,286				14,188				13,398
	Total operating expenses			21,672				17,801				61,751				55,051
	Loss from operations			(10,883	)			(10,956	)			(31,917	)			(33,888	)
	Other income
	Interest and other income, net			1,687				1,343				3,705				4,452
	Total other income			1,687				1,343				3,705				4,452
	Loss before income taxes			(9,196	)			(9,613	)			(28,212	)			(29,436	)
	Income tax expense			—				—				—				406
	Net loss		$	(9,196	)		$	(9,613	)		$	(28,212	)		$	(29,842	)
	Other comprehensive loss
	Unrealized gain (loss) on marketable securities			189				137				121				(75	)
	Comprehensive loss		$	(9,007	)		$	(9,476	)		$	(28,091	)		$	(29,917	)
	Net loss per share, basic and diluted		$	(0.72	)		$	(1.51	)		$	(3.03	)		$	(5.12	)
	Weighted average common shares outstanding, basic and diluted			12,686,122				6,351,431				9,301,740				5,827,750

FAQ

What did Assembly Biosciences announce about ABI-5366 on Nov 10, 2025?

Assembly announced positive Phase 1b interim results for ABI-5366 showing significant reductions in HSV-2 shedding and genital lesion rates.

How much cash did ASMB have at Sept 30, 2025 and how long is the runway?

ASMB reported $232.6M in cash, cash equivalents and marketable securities, projected to fund operations into late 2027.

How much did Assembly raise in the August 2025 equity financing (ASMB)?

Assembly raised $175 million in gross proceeds from equity financings in August 2025.

What were ASMB's Q3 2025 collaboration revenues with Gilead?

Revenue from collaborative research with Gilead was $10.8M for Q3 2025, versus $6.8M in Q3 2024.

When is Assembly expecting the next HSV data readout for ASMB programs?

Interim HSV Phase 1b data from two weekly ABI-1179 cohorts and one monthly ABI-5366 cohort are now anticipated by year-end 2025.

When is a Phase 2 study for ABI-5366 expected to start?

Initiation of a Phase 2 clinical study of ABI-5366 is anticipated in mid-2026.